Limiting the Effects of a Pivot Point? Little Help with an Homemade Arm Brace (with Pics!)

Try a foam rubber pad under the top bar from the round barbell holder to the lower bar to distribute the load to the forearm.

Hi Lyn, I might be misunderstanding you but would that not redistribute the weight onto the same pivot point?

If the pivot point is directly above the red arrow in the bottom picture, no. The pad would start at the arrow and run to the "wrist" end of the brace.

Tornado's radius would help, but pads would redistribute the weight away from that point.

Oh I think I understand. The only problem with that would be that it would redistribute the weight into the wrist and hand area with the pads? If so then I wouldn't be able to do it as my wrist and hand is where the injury lies. Again, I might of misunderstood!

No, my point was just that.

Maybe the radius would be better.

It might even work simply to trim an inch or so off the right end of the bottom piece. That would still concentrate some stress on your arm, but it would be away from the sensitive wrist areas.

I'd try a radius starting at the spacer block and curving gently up to the end of the lower arm.

Hi Lyn, would you be able to expand on that? I'm not quite sure what the radius refers to. I'm petroleum so its probably my lack of understanding the terminology

Sorry, gentle curve from the block upward/forward until it touches the upper bar.

Maybe done in two steps.

If you are petroleum how comes you can talk?

Sorry could not resist.

That sounds like a suitable contour.

Hi Lyn, sorry I do understand using a radius for a shadow angle! That sounds like an interesting way forward! Thanks

Hi Tornado, I think this might be the most promising way forward at this point. Thanks

I would try to make the contour of the bottom piece match more closely the contour of your arm. At present, both ends can "dig in", especially as you note at the right end. A soft rubber or foam backing might also help.

Even if your wrist and hand can't support much load right now, your scheme is a good approach for maintaining elbow strength. Good luck on optimizing this, and best wishes for full recovery.

Hi Tornado, thanks for the encouraging words. I like the idea of contouring the bottom of the piece. I may be able to do this when I attach some padding in layers. The problem I have with the right end is that even with padding it seems to put too much pressure on the one point. I'm holding out on the chance that theres a work around for this!

Hey Gringogreg! Thats a great idea. The only thing is, and I forgot to say this in the description, is that my exercises require me to do 'pressing' dumbbells too i.e. like a push up except using a dumbbell. Your idea would be perfect for the other bicep curling-type movement but unfortunately it might not take the strain of the other movement. If I've correctly understood

Good idea. With wide straps supporting it.

no amount of padding will save a poor design, any brace needs to follow the contours of your body or you'll have a similar result. you van make a mold of your arm using youtube info. if the palm of your hand is not an issue I'd make a rig that uses the same,e plane as your shoulder as a pivot point, sit and swing the weight from near your hip going up to chest height, similar to the motion of bowling

Hey Fredski, contouring the brace does make sense but in its current form, most of the weight goes through the pivot point. Because of this, just contouring around the pivot point would have virtually the same effect. Would you mind expanding on your second suggestion? I can't quite visualise it, and the image I'm getting wouldn't allow for the elbow bending so I'm likely misunderstanding

I think the only thing you can do to lessen the pain is to fashion a circular cuff that fits over your arm (like the one for the barbell, only turned 90 degrees and flipped so it fits over your arm. The secret is to make the area as large as practical to spread out the force and lessen the pressure and cushioned so that it conforms to the shape of your wrist.

Hey Rixter, I think this idea is the simplest and cheapest option thanks. I went for a gander around the house to try and find a half-pipe shaped object like you said so I could try it out. Annoyingly, I don't have anything lying around so will pop to the shops after the bank holiday to have a look for something. Thanks for the suggestion. I will update the forum with the results of the trials lol

Stop doing this to yourself! Pain is Nature's way of saying you need to find another way to exercise. Walk, run, jog, do sit ups, pull ups, jumping jacks or push ups. Get an exercise bike, elliptical trainer, step-up, treadmill, or other. NO PAIN, MUCH GAIN

Haha hey Wayne! Appreciate your concern and in the grand scheme I think your onto something. I'm naturally quite skinny so my genetics do favour the exercises you suggest! But I want try and work out a balance between these exercises and some light-medium weight training. We'll have to see how it goes!

Scan the area were you need padding. Use a 3D Cad package to match to your brace. Send file to a 3 print shop. Specify material it is to be made of, probably a nylon is okay. Press print button. You will not need soft padding as you will get 100% contact.

Hey Cristle, I didn't think of 3D printing, thats pretty interesting. The physical problem of a pivot point wouldn't be remedied by this though, if I've understood correctly? It would increase the pivots surface area on end of the brace by being shaped like the arm thus reducing the pain?

You could remove the lower part of the contraption and rater use that piece to support the back of your hand to prevent the wrist from bending away. You will have to contour both parts wit padding or casting.

PS you should do some wrist exercises as well.

What are the issues when pushing the weight.

Hey Hendrik, your idea is perfect if the movement was bicep curl type exercises (which some of it would be). The issue with pushing the weight is down to my condition being a 'ganglion cyst'. Its a fluid filled sack that can develop in joints from minor or repetitive strain (not dangerous but annoying). Because of this I need the brace to take loads in two planes i.e. bicep curls and presses. If I've understood you correctly?

Hey Fuller, not sure why you were down voted mate, it wasn't me anyway. The problem with that idea might be that upon adding a dumbbell/ weight and moving ones hand back from the cast (to prevent the weight going through the hand) the pinch would occur at the first point the weight is taken i.e. the beginning of the wrist. I'm not sure if thats explained well but I hope it might make sense?

Edit: Oh you weren't down voted you just marked as off topic?

first, as someone else had suggested, remove the bottom part of the contraption. if this is not possible, you will need another flat piece of metal that will parallel your arm and which goes under the pressure point. this will distribute the weight evenly onto your arm.

Hey Setlock, the reason why I put the bottom piece on was to distribute the pressure evenly from the middle point (where there is a joining piece from top to bottom). This, however, hasn't worked and the pressure point is still at the end. I understand what you are saying but it seems like if I put another piece under it it will just transfer the pivot point to the point nearest the weight (if that is a top piece, middle piece or from adding a new under piece). If that makes sense?

Shorten the arm and add a hinge. Attach an additional plate to distribute the weight on the arm. The additional plate should be hinged in the middle. Not long enought to place strain on the wrest.

Heyy Ozzb, sorry, I'm afraid I'm not following! By arm is that the long piece running against my forearm or the top piece joining to the dumbbell holder? I'm not grasping what the hinge would do in terms of the physics of the idea. Would you be able to expand on it? It does sound fascinating and I'm incredibly interested in understanding it. I think its also the limiting aspects of words when it comes to explaining engineering. Thanks pal!

You could have someone else lift the weight.

Okay, that was naff...

What you have is a pressure point and you can add padding or even radius the end of the metal (or both) to distribute that area where the force is imparted, but you will only be able to mitigate it so much.

However, you will always have the issue to some extent as long as you have a weight suspended on the device.

I'm not sure where the injury point is, but the best you can do is to make a contoured form that perfectly fits the forearm. Yet you will always have a pressure point at the end of the forearm where the prosthesis ends and that's just the physics of the problem. It is simply acting as a lever and the fulcrum will always be at the end of the forearm where the prosthesis ends.

If you are really intent on this I would make a padded splint that covers and conforms to your forearm as best as you can and attach the weight so that it sits on the middle of the forearm. This will better distribute the weight and make it more comfortable, but it will have some drawbacks..

Of course you will probably need to almost double the weight to get the same apparent lift force.

The downside is that you will only be able to work the bicep and brachialis muscles and not the muscles in the forearm, but you probably already figured that out.

Hey Anonymous Hero, your summary is perfect. In fact I'm tempted to rewrite my initial post and copy in yours as it is so well done (leaving aside the joke)! The being situated over the forearm, resting on the forearm with a contoured brace is very logical. Even despite the increase in weight it is a viable alternative. I've made a note of the idea along with a couple of other ideas from the thread. I'll keep you updated on any progress with the ideas. Thanks a lot for the contribution. You understand the issue better than I do which is impressive!

Just think of the problem as nothing more than a lever or even a seesaw.

OK, here's an idea. Maybe you can use a bowling glove to protect your wrist...

Ah would this go under the brace to protect the forearm like the circular cuff idea you mentioned before?

Under the brace, that's what I was thinking. They're made to fit the wrist and provide support and should spread around the pressure from your brace. It might work.

I'd recommend making a plaster cast piece that contours to your arm exactly, then put a layer of cushioning material between the plaster and your arm. The plaster cast will distribute the weight over the whole arm.

http://www.amazon.com/Pop-Art-Plaster-Bandages-1-Roll/dp/B00LIS9UPO/ref=sr_1_2?ie=UTF8&qid=1428321362&sr=8-2&keywords=plaster+casting+bandage

There are a lot of good suggestions.
DISCLAIMER!I am not a physician nor am I employed in any type of health care business. These ideas and images are just my opinion and in no way have been tested or approved by a physician. On a side note, what does your Doctor have to say about your device and the pressure it is putting on your healing wrist, arm, hand?
What I see is that you are putting all the force on the area indicated, you may need to continue the support over your wrist (see picture). The last idea of making a plaster cast of your arm is probably something you can incorporate with your metal brace. I think you need to have at least a small amount of support over the wrist area with padding.
I assume that your design is to all but eliminate the pressure on your wrist however you now transferred the pressure to your forearm. Trying to not use the hand or wrist muscles when lifting an object like the dumbbell is a difficult feat because you have to relax your wrist but do the same movement, you just don't get the full force that you think you should.
My simple explanation is to support your entire forearm and wrist and hand into one contiguous apparatus with padding at the wrist area.I added a line on your picture to describe my thought.I broke my wrist about 3 years ago, (auto accident) it HURT big time but the doctors focused on my ribs and shoulder and left the wrist as a sprain. No they never took an x-ray of my wrist. 3 weeks later I went to see my regular Dr. and he took an x-ray and found 3 fractures and by the time I saw the specialist it had already started to heal. Luckily I had been wearing a wrist support all the time and the Spec. Dr. just wrapped it in a cast stating that I was very lucky to not require surgery to correct the untreated healing process. I feel your pain.Take care and good luck with your wrist and invention!

I would think that a cradle on the bottom of your arm that support the injury but also allow the exercise to benefit the injury starting with smaller weights.You can not exercise the Humerus muscles without using the one's of the Radius and Ulna and therefore the fulcrum's and tendons in your wrist and hand. Do not make that injury worse. Better save than sorry.

Is this what you want to achieve ?
Why not move the slightly bigger weight to the "pivot point" with metal support on both sides of the forearm and wrist to prevent movement of wrist ?